Technical Abstract:
Agroforesty and grass buffer systems have long been promoted as a soil conservation practice that yields many environmental benefits. Previous research has described the ability of buffer systems to retain nutrients, slow water flow and soil erosion, or mitigate the potentially harmful effects of excess fertilizers or pesticides. These studies focused primarily on the role of vegetation and/or soil properties in these ecosystem services. Few studies have investigated the soil microbial community of buffer systems. We wished to determine potential differences in soil microbial community characteristics among agroforestry and grass buffers, and traditional cropping (i.e., soybean) systems. Soils were collected (0-10 cm depth) from agroforestry and grass buffers, and cropped areas located at the University of Missouri’s Greenley Memorial Research Center, Novelty MO (40°01’N, 92°11’W). Samples were tested for soil microbial function using Biolog ECO microplates and dehydrogenase and fluorescein diacetate hydrolysis enzyme assays. Microbial community structure was determined using phospholipid fatty acid (PLFA) analysis. Most measurements based on the ECO microplate assay (i.e., average well color development, richness, diversity and evenness) failed to show any differences in microbial community physiological characteristics. However, a principle component analysis of the substrate utilization data from the ECO microplate assay suggests that the grass buffer soil microbial community is different from the agroforestry buffer or cropping system soil microbial communities. Enzyme activities differed between the three systems, with the grass buffer system showing the greatest activity level. PLFA analysis revealed community structural differences underlying the functional differences. While there is great functional redundancy in the soil microbial community, the differences observed in this study may help explain some of the differences in buffer ecosystem services observed in other studies. Further investigations of the soil microbial community will advance our understanding of these complex agroecosystems.